Interactive Multimedia on the Web

P1: GHK/FFX P2: GHK/FFX QC: IML/FFX T1: IML

Interactive˙Media˙OLE-2 WL040/Bidgolio-Vol I WL040-Sample.cls March 17, 2003 11:12 Char Count= 0

Interactive Multimedia on the WebInteractive Multimedia on the WebBorko Furht, Florida Atlantic UniversityOge Marques, Florida Atlantic University

Introduction 1What Exactly is Interactive Multimedia? 1Multimedia Network Technologies 1

Characteristics of Multimedia Traffic 1Standards for Multimedia Communications 2

Creating Interactive Multimedia Web Pages 3Tools, Services, and Applications 4

Multimedia Portals 4Interactive E-Learning Tools and Distance

Learning Applications 5Media-Sharing Applications 5

Multiplayer Web Games 7Web 3D Virtual Environments 7Participatory Publishing 7Interactive Web Maps 7Multimedia Search Over the Web 8Integration of the Web With Traditional Media 10

Conclusion 11Appendix 11Glossary 11Cross References 12References 12

INTRODUCTIONPersonal computing, multimedia, and computer networkshave experienced a tremendous boom during the pastdecade. From expensive, stand-alone MPC-1-compatiblePCs that landed in the marketplace in the early 1990s tothe popularization of the Internet, particularly the WorldWide Web, the production, archiving, and distribution ofmultimedia has evolved from a few, technologically lim-ited devices to a plethora of hardware and software avail-able for these tasks. It is now possible to develop higherquality multimedia content, in less time, and distributeit to a much wider audience (using the Web as opposedto CD-ROMs) than anyone could have imagined a decadeago.

The Internet has become ubiquitous and is quickly ex-tending its arms to the wireless arena. The hunger formultimedia-rich content over the Web has fostered devel-opments in many fields, from the technological infrastruc-ture necessary to carry multimedia data, to the tools usedto create, manage, and distribute multimedia content. In-teractivity is the key concept in many such applications,such as games, maps, and distance learning applications.

In the first part of the chapter, we define the concepts ofmultimedia and interactivity, particularly on a Web-basedcontext, and present a summary of the network technolo-gies that enable transmission of interactive multimediainformation over the Web. In the next section, we showthe process and related languages and tools for creatinginteractive multimedia Web pages. Finally, we present anoverview of current interactive multimedia applicationsand services.

WHAT EXACTLY IS INTERACTIVEMULTIMEDIA?We start by conceptually defining “multimedia” and “in-teractivity” in the context of Web-based applications. Theterm multimedia has been frequently used to mean thecombining of text, graphics, images, sounds, and video

on one page or presentation. According to this defini-tion, most of the pages currently available on the Webare inherently multimedia. For the discussion that fol-lows, it is important to know the following. (a) multimediacontent that combines only text, images, and animations(for which there is a built-in HTML support) is differentfrom applications that use video clips, animations, andsounds (for which third-party products—usually availableas browser plug-ins—are required). A multimedia-richHTML page consisting exclusively of text, JPEG images,and animated GIFs would belong to the first category,whereas a page that loads a Macromedia Flash moviewould belong to the second group. (b) Multimedia infor-mation that is delivered without user interaction is differ-ent from multimedia contents that change dynamicallyin response to the user’s inputs. The streaming of a pre-recorded video clip would be classified under the firstgroup, whereas the constant updating of a screen in amultiplayer Web game would qualify as an example of thesecond case.

MULTIMEDIA NETWORKTECHNOLOGIESThere are five main types of communication network tech-nologies used to carry multimedia traffic (Halsall, 2001):telephone networks, data networks (including the Inter-net), broadcast television networks, integrated servicesdigital networks (ISDN), and broadband multiservice net-works, such as B-ISDN. In this chapter, we focus mostlyon the Internet. Besides enabling a number of interper-sonal communication tools, such as e-mail, the Inter-net also hosts a large number of interactive multimediaapplications stored in Web servers.

Characteristics of Multimedia TrafficInteractive multimedia may be real-time or non-real-timeinformation. Real-time, or continuous, information istransferred from source to destination as it is generated

1



INTERACTIVE MULTIMEDIA ON THE WEB2

and is played out at the destination as it is received. Thismode of operation is commonly known as streaming. Au-dio and video streaming over the Web have become verypopular over the past few years. Examples include ra-dio and TV broadcasting over the Web. In non-real-time,or block-mode, media, the information is generated andstored in a way that is not time sensitive and is down-loaded by request by interested users.

Multimedia traffic can be classified into two maintypes: constant bit rate (CBR) and variable bit rate (VBR).Audio streams, for example, are typically generated at aconstant rate, determined by the sampling frequency andnumber of bits per sample used to convert the audio in-formation into digital format. Video streams, on the otherhand, exhibit VBR, even though the frames that make up avideo program are generated and displayed at a constantrate. This is due—among other things—to the fact thatmost video compression algorithms use differential tech-niques that employ fewer bits on frames that resembleprevious frames.

The transfer of multimedia information streams be-tween any source and destination of can occur in a num-ber of different ways.

Simplex: Information flows in one direction only.

Half-duplex: Information flows alternately in both direc-tions.

Full-duplex: Information flows in both directions simulta-neously.

Unicast: Information flows from the source to a singledestination.

Multicast: Information flows from the source to multipledestinations, comprising a subset of the nodes con-nected to the network.

Broadcast: Information flows from the source to all desti-nations connected to the network.

In the case of half- or full-duplex communications, theflow of information can be symmetric, where each partysends a comparable amount of information to the other, orasymmetric, where the flow of information is much higherin one direction than in the other.

The Internet uses packet-switching techniques to trans-fer information between two end computers using inter-mediate nodes—routers—along the way. This mode ofoperation is also sometimes referred to as store-and-forward, indicating that there is a built-in delay in theprocess that occurs every time a packet arrives at a routerand waits for the router’s decision (upon looking at itsrouting tables) as to where the packet must be forwardednext. The sum of the store-and-forward delays in eachrouter contributes to the overall end-to-end delay betweensource and destination. The average of this delay is knownas mean packet transfer delay and the variance is usuallyknown as delay variation or jitter. The inevitability of thesedelays is one of the technical challenges behind enablinginteractive multimedia applications on the Web.

Besides the delay limitations, the Internet has anothercharacteristic that makes for less-than-ideal conditionsfor carrying multimedia traffic: It offers a best-effort ser-vice to its end users, which means that the TCP/IP-based

transfer of packets is subject to errors (damaged pack-ets, lost packets, timeouts, etc.), and the typical way tohandle such errors is to discard packets and (optionally)request/wait for retransmission. Because much of multi-media traffic may be sensitive, retransmissions are usu-ally not desired, because they add up to traffic inside thenetwork and also because by the time the retransmittedpacket arrives, it is no longer needed. A common way ofhandling with lost/retransmitted packets while providingthe user with the illusion of continuous flow of informa-tion is the use of buffers at the receiving side.

Designers of networked multimedia applications usu-ally specify the minimum network requirements that mustbe met to enable the application to work. These require-ments are collectively known as network Quality of Ser-vice (QoS) parameters. Examples of QoS parameters aremaximum packet size, average bit rate, average packeterror rate (PER), mean packet transfer delay, worst-casejitter, and transmission delay. In addition to the networkQoS parameters, the application itself has QoS parame-ters associated with it, such as the required bit rate ormean packet transfer rate, the maximum start-up delay,the maximum end-to-end delay, the maximum jitter, andthe maximum round-trip delay. To simplify the process ofdetermining whether a network meets the QoS require-ments of a particular application, several service classeshave been defined, each of which contains a specific setof QoS parameters. A network may support two or moreservice classes, in which case different classes are usuallyassigned different priorities.

Standards for Multimedia CommunicationsMultimedia information is typically transmitted in com-pressed form over the Web. Many standards have recentlybeen developed for image, audio, and video compressionand transmission. The most important standards are asfollows.

MPEG-1: The first widely deployed standard proposed bythe Motion Pictures Expert Group (MPEG). It aims ataudiovisual encoding at a bit rate of 1.5 Mbps, whichallows for VHS-like video with stereo audio to be en-coded and which is stored in a CD-ROM. The best-known contribution of the MPEG-1 standard is its layerIII audio compression, popularly known as MP3, whichcaused an entire revolution in the music industry.

MPEG-2: Enables the transmission of audio and videoover broadband networks. It aims at encoding digi-tal TV (and HDTV) signals and has been widely usedin the consumer electronics field, from delivery of TVprogramming via personal satellite (dish) systems, toDVDs, to personal digital video recorders such as TiVo.

MPEG-4: Follows an object-based representation ap-proach to audiovisual scenes, where each scene is com-posed of objects, both natural and synthetic. MPEG-4-based systems are not yet fully deployed at a consumerlevel at the time of this writing. It is expected, though,that the object-based nature of the standard will signif-icantly enhance interactive multimedia applications.

MPEG-7: Standard that describes multimedia content, en-abling users to search, browse, and retrieve multimedia



CREATING INTERACTIVE MULTIMEDIA WEB PAGES 3

Internet

User interface(Web browser)

Applicationstandards

Network interfacestandards

Managementinterface

Applicationstandards

Network interfacestandards

Networkinterface

Networkinterface

Client Server

Internalnetwork

standards

Figure 1: Standards requirements for interactive multimediaapplications over the Internet.

contents more effectively than current text-basedmethods allow.

MPEG-21: The latest effort of the group focuses on provid-ing a multimedia framework that should enable trans-parent use of multimedia resources across a wide rangeof networks and devices.

JPEG and JPEG 2000: The JPEG (Joint Photographic Ex-perts Group) compression standard for still images wasdeveloped in the late 1980s and has become tremen-dously popular. JPEG 2000 is a new standard that usesWavelet subband coding techniques and allows for nu-merous compression options. It has recently been ap-proved and is starting to enjoy some popularity amongInternet imaging users.

In the context of interactive multimedia applicationson the Web (Figure 1), standards are required both atthe application and at the networking level. Examples ofapplication-level standards include the JPEG and MPEGcompression standards and the hypertext transfer proto-col (HTTP) implemented by all Web browsers to allowHTML pages to be displayed at the client’s side. Network-level standards include the TCP/IP protocol suite.

CREATING INTERACTIVE MULTIMEDIAWEB PAGESContemporary tools for designing Web pages (such asMacromedia Dreamweaver and Microsoft FrontPage) al-low the inclusion of multimedia objects, such as videos,images, animation, and audio, in Web pages. To playsound, animation, and video, the user system may requireplug-ins, which are small programs that work in coopera-tion with a Web browser. Some plug-ins have become verypopular, so Netscape and Microsoft browsers have builtthem into their latest versions. Popular multimedia plug-ins include RealNetwork’s Real Audio and Real Video, Ap-ple’s Quick Time, and Macromedia Shockwave and Flash.

Besides plug-ins, which allow multimedia objects to beincluded in Web pages, more sophisticated Web pages alsoinclude Java Applets and VRML (virtual reality modeling

language) three dimensional (3D) images. Java Applets areprograms embedded in Web pages (in HTML code) andused to create multimedia Web pages that include anima-tion, sound, images, and videos. The Applet runs locallyon the client machine, which is running a Web browser.VRML is a generic text-based language used to construct3D images and 3D text for Web pages. A VRML documentis an ASCII file, much like an HTML document. In VRML,the Web designer specifies objects—called nodes—that de-fine shapes and their attributes. These nodes create 3Dscene graphs, which a VRML browser renders. Examplesof nodes include cube, sphere, cone, cylinder, rotation,and scan.

Although including all these components makes Webpages multimedia rich, it does not make them interactive.The complete process of creating interactive multimediaWeb pages, and the related tools and languages, is shownin Figure 2. This process is described next.

The original (home) Web pages, hosted at a server, in-clude multimedia objects (such as music, sound, images,animations, and video clips), Java Applets, and VRML im-ages. To provide interactivity, a Web designer should alsoapply client-side and/or server-side scripting.

Client-side scripting includes CGI (Common GatewayInterface) scripts that provide interactivity by processingand responding to user inputs. When a user submits anHTML form, a program that resides on the server systemreceives and processes the form’s content. This programthen creates an HTML document dynamically, which theserver displays back to the user on the client machine.CGI scripts are usually created using Perl, JavaScript, orVBScript.

Perl is an interpreted scripting language for process-ing data collected from HTML forms, which is well suitedfor text manipulation. Its features include flexibility, com-pact, form, security, and support for file and databaseoperations.

JavaScript is another scripting language that is usedto create and process Web pages with HTML forms.However, the browser, and not a program on the server,executes JavaScript, adding interactivity and dynamiccontent to Web pages.

Java Media Framework (JMF) tools provide the inte-gration into Java applications and Applets of a wide rangeof audio and video formats, advanced imaging, animation,2D and 3D graphics and modeling, as well as speech andtelephony support. The JMF consists of a suite of Javamedia APIs (Application Programming Interface).

JMF player API is used by applications and Applets tocreate and control media playback. Java 2D API (J2D) and3D API (J3D) provide sets of classes for writing 2D and 3Dgraphics applications and Applets, respectively. Java Ad-vanced Imaging API allows sophisticated image process-ing to be incorporated into Java Applets and applications.

VBScript is a scripting language from Microsoft that isbased on Visual Basic, which is used to create interactivemultimedia Web pages. Like JavaScript, VBScript state-ments are embedded in an HTML code, which a browserexecutes. VBScript provides access to OLE (Object Link-ing and Embedding) objects, called ActiveX controls.

ActiveX is an OLE object, which is a class library thatcontains a complete set of functions for manipulating an




Figure 2: A process and tools in creating interactive Web pages.

object. The code for an OLE object already exists, so pro-grammers can include the objects in applications quicklyand easily. ActiveX controls provide programmers witha way to extend browser capabilities and create a widerange of Web site capabilities. Some examples of ActiveXcontrols include button (control to display various framesequences), chart (enables the programmer to draw var-ious types of charts with different styles), and gradient(shades the area with a range of colors).

Server-side scripting provides an effective way to dy-namically build documents in response to client (or user)requests. As shown in Figure 2, server-side scripting usesinformation sent by clients, information stored on theserver, and information from the Internet to dynamicallycreate Web pages (in XHTML or XML), which are thensent back to the client.

Active Server Pages (ASP) is a popular server-side tech-nology from Microsoft, which is processed by an ActiveXcomponent (server-side ActiveX control) called a scriptingengine. An ASP file has an extension .asp and containsXHTML tags and scripting code. The VBScript is mostwidely used for ASP scripting, but other languages, suchas JavaScript, can be also used.

Scalable Vector Graphics (SVG) is a Web standard thatspecifies the language for describing two-dimensionalgraphics in XML. It will provide the next-generation Webbrowsers with native support for multimedia. SVG allowsfor three types of graphic objects: vector graphic shapes(e.g., paths consisting of straight lines and curves), im-ages, and text. Graphical objects can be grouped, styled,transformed, and composited into previously rendered

objects. Text can be in any XML name space suitableto the application, which enhances searchability and ac-cessibility of the SVG graphics. The feature set includesnested transformations, clipping paths, alpha masks, filtereffects, template objects, and extensibility. SVG drawingscan be dynamic and interactive. The Document ObjectModel (DOM) for SVG, which includes the full XML DOM,allows for straightforward and efficient vector graphicsanimation via scripting.

In summary, a number of tools, languages, and com-ponents, which are introduced in this section, are used tocreate contemporary and effective interactive multimediaWeb pages.

TOOLS, SERVICES, AND APPLICATIONSToday, there is a wide range of interactive multimediaservices and applications on the Web. In this section, wediscuss the basic services and applications as well as re-lated tools. The list of these services and applications isgiven in Table 1.

Multimedia PortalsMarket environment is changing rapidly and thereforenew functionality is important for gaining competitiveadvantage. Time-to-market is critical, and businessesneed to integrate systems, automate processes, andprovide each other with access to key functionality.Recently, Web portals evolved as a single, integratedpoint of access of information, applications, and people.Web portals are Web sites that offer a great deal of



TOOLS, SERVICES, AND APPLICATIONS 5

Table 1 Interactive Multimedia Services and Applications on the Web

APPLICATION DESCRIPTION

Multimedia portals (sampleURL:http://www.eUniverse.com)

Give users single, customizable access to multimedia services,including video, audio, animation, interactive banners,etc; can be classified as entertainment, educational, andinformation portals.

Interactive e-learning and distance learning (sampleURL:http://www.click2learn.com)

Applications include a wide variety of media files tointeractively explain complex concepts; distance learningallows customers to subscribe to online courses taught atremote sites.

Media sharing (sample URL:http://www.ic.media.mit.edu)

Provides collaborative music and video production by a groupof artists from dispersed locations.

Interactive multiplayer games (sampleURL:http://www.sierra.com)

Games in which multiple players participate over the Internet.

Web 3D virtual environments (sampleURL:http://www.parallelgraphics.com)

3D content that allows users to fly through virtual space.

Participatory publishing Web content that users, along with authors, can contribute toand influence.

Interactive Web maps (sampleURL:http://www.archaeology.usyd.edu.au/research/time map)

Time-enabled maps that typically display archeological andhistorical data.

Multimedia search over the Web (sampleURL:http://www.fastsearch.com)

Web-based search systems that provide search results as imagesand audio and video files on a single result page.

Integration of the Web with traditional media (sampleURL:http://www.broadcast.com/television)

Applications include radio and television broadcasting on theWeb, video-on-demand, and interactive TV applications.

content and services. They integrate new content withexisting content, server-side applications, and Web-basedservices. There are two basic Web portals: (a) publicportals, such as Yahoo, which bring together informationfrom various sources, applications, and people, andwhich offer personalized Web sites; and (b) enterprise,or usiness, portals, which give employees access toorganization-specific information and applications.

In another classification, a horizontal portal providesa gateway to a broad range of information, whereas avertical portal provides in-depth information about aspecific topic.

Multimedia portals are special Web portals that offermultimedia services, such as streaming video, audio, in-teractive banners, and animation (Dimitrova et al., 2000).Multimedia portals can be classified as belonging to oneof the following groups. (a) Entertainment portals typicallyprovide customizable music, television, and movie news.For example, a portal from Warner Brothers, shown inFigure 3, provides features such as an e-mail center; cus-tomizable access to music, DVD videos, television, andmovies; entertainment news; a chat room; and interactiveadvertiser banners. (b) Educational portals include onlinelearning applications that provide access to diverse setsof content. An example of a tool for developing educa-tional portals is the Aspen Learning Content ManagementServer from click2learn (http://www.click2learn.com),which allows a team of instructional designers, media de-velopers, subject experts, and content reviewers to worktogether effectively through project management, work-flow, and collaboration. (c) Information portals provideusers with the means to find information on any topic(such as Yahoo).

Interactive E-Learning Tools and DistanceLearning ApplicationsThe Web coupled with multimedia content has thepotential to change how people are educated. Con-temporary e-learning tools allow the development ofonline interactive learning applications. An exampleof such a tool is ToolBook Instructor and Assistant(http://www.click2learn.com), which supports a wide vari-ety of media files, including sound, animation, streamingmedia, and still images. Some interactive learning appli-cations using ToolBook include innovative technical andmaintenance training, electronic service manuals, andsoftware training courses. Figure 4 shows a screen fromthe interactive Boeing 777 course, showing how skilledaircraft mechanics share techniques for installing safetyhardware in confined spaces.

Distance learning allows remote participants to receiveclasses over the Internet. Advanced distance learning sys-tems include a real-time interactive virtual classroom,which allows a remote participant not only to receive alive class feed but also to interact in a live class using audioand video over the Internet (Deshpande & Hwang, 2001).

Media-Sharing ApplicationsMedia sharing includes the design of tools that supportcollaborative music or video production by a group ofartists from geographically dispersed areas. A sharablemedia project team at MIT Media Lab, led by GloriannaDevenport (http://www.ic.media.mit.edu), has developeda set of tools that allows online groups of filmmakersto collaborate on the same film project by contributing




Figure 3: An example of the entertainment portal from Warner Brothers. (Fromhttp://www.entertaindom.com.)

and sharing material, and to comment on one another’screations (Kelliher et al., 2000). An example from thisproject is PlusShorts application, which is implementedas a Java Applet, and which allows distributed groupsof users to contribute and collaborate in the creation ofshared movie sequences.

RocketNetwork (http://www.rocketnetwork.com) hasdeveloped a tool for online musicians that provides simul-taneous access to audio files and allows the collaboration

of musicians and producers. This system, referred toas “global production network,” allows the dynamicupdating of files from anywhere in the world. Applicationsinclude sound track production for film, TV, and radio,and sound tracks for broadcast media.

The system is based on a RocketNetwork’s centralserver, which coordinates sharing, dynamically updates,and distributes audio and MIDI (Musicial Instrument Dig-ital Interface) files.

Figure 4: Boeing 777 interactive maintenance course created using the ToolBooke-learning tool. (From http://www.click2learn.com.)




Figure 5: Half-life from Sierra.com—illustration of a multiplayer Web game. (Fromhttp://www.sierra.com.)

Multiplayer Web GamesInteractive multiplayer games allow multiple players toparticipate in games over the Internet. The challenge ofWeb-based multiplayer games is in the quality of theconnection and the ability of the designer to implementthe plot in a cyberspace way. Real-time games also re-quire that players visit a chat room and register andthat all clients be synchronized. Figure 5 illustrates anexample from the game Half-Life, created by Sierra.com(http://www.sierra.com).

Web 3D Virtual EnvironmentsSupport for VRML in Web browsers allows developers topresent their content in 3D rather than just as documents.The user can “fly” through virtual space and experience areal car, house, or town. The browser requires a plug-in,a Web browser that provides complex VRML rendering.Figure 6 illustrates the Cortona VRML plug-in, by Paral-lelGraphics for a 3D model of a sport car.

The same company, ParallelGraphics, offers Out-line3D, an interior design application that enables usersto quickly customize a virtual environment specific totheir design needs (http://www.parallelgraphics.com). Po-tential applications include (a) a 3D room for potentialbuyers to view the finished interior design of an office ora home, and (b) real estate applications, for real estateagents to show customers the look of their future home.

Participatory PublishingParticipatory publishing refers to Web pages where read-ers can contribute and influence the content along withauthors.

An example of participatory publishing is WebTour, anapplication developed by the Siemens Research Center in

Princeton, in which viewers can make verbal commentsand dynamic annotations or drawings to illustrate somepoints. The system is capable of recording, playing back,storing, searching, and distributing personalized dynamicmultimedia annotation on Web documents in the form ofguided Web tours.

Potential applications of participatory publishingtools, including WebTour, include the following.

E-commerce: When a customer enters the Web site ofa retail store, a Web clerk greets the customer andguides him/her through various Web pages explainingkey products and adding advertisements when neces-sary.

Corporate Intranet: Different users, such as employeesand/or customers, can make annotations on the sameWeb document and share ideas.

Distance learning: A teacher can make annotations on Webpages explaining complex problems. The annotationscould then be retrieved by students and played back.

WebTour is implemented using open Web technologies de-scribed earlier—standard browsers, Java, dynamic HTMLand JavaScript, and Active Server Pages.

Interactive Web MapsInteractive Web maps are time-enabled maps createdfrom distributed databases. Interactive maps typically dis-play archaeological and historical data, such as historicalmaps and images, the growth of cities, the spread of dy-nasties and empires, or the distribution of archeologicalsites. However, there is a wide range of other applications,which could include time-stamped data. Interactive Webmaps could also link map objects to images, other Webpages, multimedia, or a database. In addition, interactive




Figure 6: VRML model of classic sport cars. The navigation buttons allow the userto change views, open the door, and change the car’s movement. (From http://www.parallelgraphics.com.)

features include zooming and panning, temporal filtering,data-driven hotlinks, and other functionality.

An example of a tool for creating interactive Web mapsis TimeMap, from the University of Sydney (http://www.archaeology.usyd.edu.au/research/time map). Figure 7 il-lustrates an interactive map developed by the TimeMapteam for the international Dunhuang project and theBritish Library. By selecting an area and clicking themouse, the viewer can access another interactive screen(Figure 8). This interactive map allows the viewer to se-lect and view archeological sites, monumental remains,routes, and so forth.

Multimedia Search Over the WebToday, there are more that 275 million multimedia fileson the Web. On average, Web surfers interact with sitescontaining multimedia content up to 25 times longer thanwith sites with static content.

FAST Multimedia Search (http://www.fastsearch.com)is currently one of the largest integrated multimediasearch products on the Internet, allowing users to receiveresults for image, audio, and video files on a single, resultspage. Users simply search by keyword, and as a result, allretrieved multimedia files are accessible from the results

Figure 7: An example of an interactive Web map. The user can click and select an area that bringsthe next interactive screen. (From http://www.archaeology.usyd.edu.au/research/time map.)




Figure 8: The user can select to view archeological sites, monumental remains, routes,and so forth. (From http://www.archaeology.usyd.edu.au/research/time map.)

Figure 9: Lycos offers the largest integrated multimedia search engine on the Web. It includes60 million images, sounds, and videos. (From www.multimedia.lycos.com.)




(b)

(a)

Figure 10: (a) An image is presented to the system and real-time image analysis isperformed by extracting features of the image. (b) The system then matches thesefeatures with the features of images in the database and retrieves similar images.(From http://www.ltutech.com.)

page. This tool has been used by Lycos to create their mul-timedia search engine (http://www.lycos.com), which isillustrated in Figure 9.

Another, more advanced search of the multimediarepository is content-based retrieval, where the user pro-vides information about the actual contents of the image,audio, or video data, rather than just keywords (Marques& Furht, 2002). A content-based search engine translatesthis information to query the multimedia database andretrieve the candidates that are likely to satisfy the user’srequest.

An example of a commercial content-based image re-trieval system is a product suite from LTU Technologies(http://www. ltutech.com), which includes five prod-ucts: Image-Filter, Image-Indexer, Image-Seeker, Image-Shopper, and Image-Watcher. The core of the system isa high-level perceptual image analyzer that is capable of

indexing, recognizing, and describing images accordingto their visual features. Figure 10 illustrates the operationof the system.

Integration of the WebWith Traditional MediaThere is a growing trend in integrating the Web withtraditional media, such as radio and television. As thestreamed multimedia protocols for audio and video havematured, a number of radio and television stations havebegun offering live and near-live audio and TV contentover the Web. Examples include Yahoo! Broadcast radioand television Web sites (http://www.broadcast.com/radioand http://www.broadcast.com/televsion).

In addition, some programs are capable of supportingactive user feedback, and even participation, so we can



GLOSSARY 11

expect a number of new video-on-demand and interactiveTV applications.

CONCLUSIONThe synergy between new multimedia technologies andthe Web have brought new delivery mechanisms and newtypes of applications. We are still in the first phase of thismarriage, where we are faced with such technical chal-lenges as how to efficiently transmit multimedia data overthe Internet and how to best use our new tools. However,the focus is already moving to new areas, such as a newway to refer to publishing, how mass media can betterreach and involve their audiences, and how to users canbetter access the Web’s wealth of multimedia information(Wynblatt et al., 2000).

APPENDIXThe following is a list of Web resources.

Multiplayer Gameshttp://www.sierrastudio.com/games/half-lifehttp://www.microsoft.com/gameshttp://www.uo.comhttp://www.cryo-networks.com/uk/cryonetworks.htmhttp://www. idsoftware.comhttp://www.epicgames.com

Web Multimedia Portalshttp://www. eUniverse.comhttp://www. tollywoodlive.comhttp://www.oz.net/blamhttp://www.click2learn.com

Interactive Web Mapshttp://www.eparka.comhttp://www.hexatech.comhttp://www.archaeology.usyd.edu/au/research/time map

Web Multimedia Search Engineshttp://www.fastsearch.comhttp://www.multimedia.lycos.com

Content-Based Search Engineshttp://www.ccrl.com/amorehttp://www.qbic.almaden.ibm.comhttp://www.ctr.colombia.edu/WebSEEKhttp://www.convera.comhttp://www.virage.comhttp://www.cobion.comhttp://www.lutech.com

Radio and Television Broadcasting Over the Webhttp://www. broadcast.com/televisionhttp://www. broadcast.com/radio

GLOSSARYActive Server Pages (ASP) Server-side technology from

Microsoft that is used to dynamically create documentsin response to user requests.

ActiveX An OLE object, which is a class library that con-tains a complete set of functions for manipulating anobject. It is used to create a wide range of Web sitecapabilities.

Client-Side Scripting Scripts embedded in Web pagesthat provide interactivity by processing and respondingto user inputs.

Constant Bit Rate (CBR) A type of network service inwhich the amount of network traffic follows a regu-lar pattern, proportional to the amount of informationthat is being transferred.

High Definition Television (HDTV) An imaging sys-tem with a resolution of approximately twice that ofconventional television in both the horizontal and ver-tical dimensions, and a picture aspect ratio of 16:9.

Java 3D (J3D) API Provides a set of classes for writing3D graphics for Java applications and Applets.

Java Applets Programs that are embedded in Web pagesand can be used to create multimedia Web pages.

Java Media Framework (JMF) Tools that provide theintegration into Java applications and Applets of a widerange of audio and video formats, advanced imaging,animation, 2D and 3D graphics and modeling, as wellas speech and telephony support.

JavaScript A scripting language that can be used to cre-ate interactive multimedia Web pages.

Jitter Refers to the variance of the overall end-to-enddelay between source and destination in a packet-switched network.

Joint Photographic Experts Group (JPEG) Respon-sible for definition of a standard widely adopted forencoding and compression of digital images.

Mean Packet Transfer Delay The average value of theoverall end-to-end delay between source and destina-tion in a packet-switched network.

MPC-1 Part of a set of standards that defined minimumhardware and system software specifications for PChardware for the earliest multimedia PCs. MPC-1, par-ticularly, was based on Intel’s 386SX processor. The lastMPC standard published was MPC 3. There are cur-rently no plans for the publication of any additionalMPC standards.

Motion Pictures Expert Group (MPEG) Responsiblefor definition of several standards widely adopted forencoding, compression, and description of audiovisualcontents.

Packet Switching Refers to a switching technique bywhich the information to be transferred betweentwo end computers is divided into packets and re-layed through intermediate nodes (routers) alongthe way.

Quality of Service (QoS) A collection of applica-tion and/or network requirements that must be metto enable an application to work on a specificnetwork.

Server-Side Scripting Provides a way to build Web doc-uments in response to user requests on the server side.Besides the information sent by users, it also usesinformation stored on the server and from the Inter-net to dynamically create Web pages.

Streaming Refers to the continuous transfer of infor-mation from source to destination.




Transmission Control Protocol/Internet Protocol(TCP/IP) A standard network protocol stack used onthe Internet and on many private networks.

Variable Bit Rate (VBR) A type of network service inwhich the amount of network traffic may follow an ir-regular pattern, mainly because of the nature of com-pression algorithms used at the source.

VBScript A scripting language from Microsoft that isbased on Visual Basic. It is used to create interactivemultimedia Web pages.

Virtual Reality Modeling Language (VRML) A text-based language used to construct 3D images and 3Dtext for Web pages.

CROSS REFERENCESSee Active Server Pages; ActiveX; Circuit, Message, andPacket Switching; Collaborative Virtual Reality (VirtualReality on the Internet); Java; JavaScript; Multimedia;VBScript (Microsoft Visual Basic, Scripting Edition); VideoStreaming.

REFERENCESDeshpande, S., & Hwang, J.-N. (2001). A real-time inter-

active virtual classroom multimedia distance learningsystem. IEEE Transactions on Multimedia, 3(7), 432–444.

Dimitrova, N, Yu, H., Galliano, F., Koenen, R., Zakhor,A., & Bouman, C. (2000). Entry into the content forest:The role of multimedia portals. IEEE Multimedia, 7 (3),14–20.

Halsall, F. (2001). Multimedia communications: Applica-tions, networks, protocols, and standards. Harlow, U.K.:Addison-Wesley.

Kelliher, A., Seo, J.J, Pan, P., Lin, C., & Davenport, G.(2000). Visual interfaces for shareable media. ISEA2000 International Symposium on Electronic Art. Au: Please

provide URLofDavenport’sWeb site andthe date youaccessed it

Marques, O., & Furht, B. (2002). Content-based videoand image retrieval. Norwell, MA: Kluwer AcademicPublishers.

Wynblatt, M., Benson, D., & Hsu, A. (2000). Multimediaapplications on the internet. In B. Furht (Ed.), Hand-book of Internet Computing (pp. 307–331). Boca Raton:CRC Press.

Interactive Multimedia on the Web

Documents

Transcript of Interactive Multimedia on the Web